A holograph is a document written entirely in the handwriting of the person whose signature it bears. Some countries (e.g., France) or local jurisdictions within certain countries (e.g., some U.S. states) give legal standing to specific types of holographic documents, generally waiving requirements that they be witnessed. One of the most important types of such documents are holographic last wills.

The expansion of the concept of holographic, or handwritten documents must include a discussion of the effectiveness of a document in accomplishing its intended purpose. Print media came into being as a solution to the problem of the sluggish and ponderous task of transcribing written materials by hand. Printing enabled rapid construction, compilation and production of written material and provided a means for the revolutionary concept of dissemination of copies of written material.

The intrinsic value of employing the handwritten word in creating a document is that the authorship of handwritten documents is able to be authenticated by handwriting comparison with samples of the author's other writings or by recognition by witnesses familiar with the handwriting style and characteristics of the author. This valuable quality of proof of authorship maintains to this day the primacy of the hand-written document where it was required, by law or by necessity, to have authenticity and verifiable provenance or origin of the document.

Of particular importance to law and society was to have the ultimate document requiring authenticity—a last will and testament—retain its authenticity, thereby accomplishing its author's intended purpose: that of making a valid, indisputable disposition of the author's real property, personal assets and wishes or declarations, at the time of his or her death.

The rule for creating a minimally acceptable "holographic" will has been agreed upon: to be indisputably without edit or revision by an outsider (other than the author), absolutely no mechanically printed material must be contained in the document. It must not be typeset, typewritten, mechanically printed or scribed by any means other than by the hand of the original author. This rule does not, however, apply to non-material terms of the will. As a result, so-called "form wills" purchased at stationery stores can constitute legally valid holographic wills provided that their material terms are completed solely in the testator's handwriting.

The will must be dated at the time of its writing, so that it can be compared (visually, forensically) with documents originating from the same author at other times, such as an earlier will (which might be intended by its author to be withdrawn or revoked by a later written will).

To be effective as a testamentary document, a "holographic" will must be signed by its author. Unlike a typewritten or word-processed "formal" will, where usually two disinterested witnesses are required to attest to the author's signing or "execution" of the document, a holographic will does not require any witnessing or notarization (an accepted form of witnessed certification of authenticity) in order to be a proper and valid testamentary instrument (document) having full legal force and effect.